1. Technical Field
The present invention relates to seats of power wheelchairs, and more particularly, to a seat reclining mechanism for a power wheelchair.
2. Description of Related Art
Power wheelchairs, such as electric wheelchairs or motorized wheelchairs are mobility assistive devices commonly provided to disabled people or bed-bound patients for allowing them to move self-reliantly. Thus, good adaptability and maneuverability are obviously important in wheelchairs. For meeting such need, some wheelchairs may be equipped with reclining chairs for providing the users with comfortable and convenient usage.
As everyone knows, a chair is basically composed of a seat portion and a back portion, which is settled roughly perpendicular to the seat portion. A pair of arm rests and footrests may be also attached for the user's comfort. Further, the seat is preferable to possess position angle variability for providing convenience to the user for his movement between the wheelchair and a bed under or without others' assistance. Thus, it is desirable that a seat of a wheelchair can be reclined into a flat shape. To form such flat shape, the back portion has to perform a pivot motion with about a 90-degree pivot angle and the arm rests as well as footrests have to move toward an altitude approximately close to the seat.
Since the center-of-gravity position of a human body can consequently shift from hips toward the lumbar and back regions during reclining, person sitting on a reclining chair designed without consideration of gravity adjustment may fall down therefrom during operation of the reclining mechanism. Thus, a need exists for a seat reclining mechanism, which is capable of reclining the back portion and shifting the seat portion thereof in harmony with the center-of-gravity position of the wheelchair it is attached to synchronously.